TY - JOUR
T1 - Two-photon excitation of ethidium bromide labeled DNA
AU - Malak, Henryk
AU - Castellano, Felix N.
AU - Gryczynski, Ignacy
AU - Lakowicz, Joseph R.
N1 - Funding Information:
This work was supported by NIH National Center for Research Resources RR-08 I 19. FNC is supported by a NIH postdoctoral fellowship (GM 18653).
PY - 1997/9/1
Y1 - 1997/9/1
N2 - We examined the steady state and time-resolved emission of DNA stained with ethidium bromide (EB) when excited with 90 fs pulses from a mode-locked titanium sapphire laser. Over the wavelength range from 840 to 880 nm EB-DNA was found to display two-photon excitation, with a cross-section near 7 X 10-50 cm4s/photon. Frequency-domain intensity decay measurements revealed similar multi-exponential intensity decays for one- and two-photon excitation. Time-resolved anisotropy decay measurements revealed similar correlation times, but different amplitudes as has been observed previously for two- versus one-photon excitation. These results indicate that two- photon excitation of EB-DNA can be accomplished with the fundamental output of a Ti:sapphire laser without obvious heating or perturbation of the DNA.
AB - We examined the steady state and time-resolved emission of DNA stained with ethidium bromide (EB) when excited with 90 fs pulses from a mode-locked titanium sapphire laser. Over the wavelength range from 840 to 880 nm EB-DNA was found to display two-photon excitation, with a cross-section near 7 X 10-50 cm4s/photon. Frequency-domain intensity decay measurements revealed similar multi-exponential intensity decays for one- and two-photon excitation. Time-resolved anisotropy decay measurements revealed similar correlation times, but different amplitudes as has been observed previously for two- versus one-photon excitation. These results indicate that two- photon excitation of EB-DNA can be accomplished with the fundamental output of a Ti:sapphire laser without obvious heating or perturbation of the DNA.
KW - Chromosomes
KW - DNA
KW - Ethidium bromide
KW - Fluorescence microscopy
KW - Fluorescence spectroscopy
KW - Imaging
KW - Multi-photon microscopy
KW - Three-photon excitation
KW - Time-resolved fluorescence
KW - Two-photon excitation
UR - http://www.scopus.com/inward/record.url?scp=0030831009&partnerID=8YFLogxK
U2 - 10.1016/S0301-4622(97)00017-3
DO - 10.1016/S0301-4622(97)00017-3
M3 - Article
C2 - 9397517
AN - SCOPUS:0030831009
SN - 0301-4622
VL - 67
SP - 35
EP - 41
JO - Biophysical Chemistry
JF - Biophysical Chemistry
IS - 1-3
ER -